Russian President Vladimir Putin, left, welcomes President Obama at the start of the G-20 summit on Sept. 5, 2013, in St. Petersburg. / Alexander Nemenov, AFP/Getty Images

by Alex Beall, USATODAY

by Alex Beall, USATODAY

Presidents Obama, George W. Bush and Bill Clinton held a cautiously optimistic view of Russian leader Vladimir Putin during their early interactions.

Over the course of these relationships, however, each president admitted political differences.

Here's a list of quotes that encapsulate their attitudes toward Putin:

Obama's comments on Putin

"I've said that we need to reset or reboot the relationship there. Russia needs to understand our unflagging commitment to the independence and security of countries like a Poland or a Czech Republic. On the other hand, we have areas of common concern." March 2009

"I don't have a bad personal relationship with Putin. [...] I know the press likes to focus on body language, and he's got that kind of slouch, looking like the bored kid in the back of the classroom. But the truth is, is that when we're in conversations together, oftentimes it's very productive." August 2009

"This is not the Cold War, this is not a contest between the United States and Russia. [...] I don't think that Mr. Putin has the same values that we do." September 2013

"The Russian people need to know, and Mr. Putin needs to understand, that the Ukrainians shouldn't have to choose between the West and Russia. We want the Ukrainian people to determine their own destiny, and to have good relations with the United States, with Russia, with Europe, with anyone that they choose." March 2014

Bush's comments on Putin

"I looked the man in the eye. I found him to be very straightforward and trustworthy. [...] I was able to get a sense of his soul." June 2001

"In 1968, America and the Soviet Union were ... bitter enemies. Today, America and Russia are friends." May 2002

"He doesn't want anybody telling him how to run his government." July 2005

"Do I trust him? Yes, I trust him. Do I like everything he says? No. And I suspect he doesn't like everything I say. But we're able to say it in a way that shows mutual respect." June 2007

Clinton's comments on Putin

"Russia has to find the right balance between the use of effective force and a decent respect for individual rights and international norms. In Chechnya, that balance has not yet been found." January 2000

"[Putin] has expressed a genuine commitment to economic reform." March 2000

"[The] world demands that we take every opportunity we can to find common ground, and that where we cannot find it, we express our differences with clarity." June 2000

"President Yeltsin led Russia to freedom. Under President Putin, Russia has the chance to build prosperity and strength while safeguarding the rule of law." June 2000